CODEWITHSUNDEEP
javaandroidgoogle-mapsarraylist
Marshall
Marshall

Reputation: 1362

Sort and merge arraylist

I have an ArrayList> called coordinates which has 3 lists: one with a variable called hr, one with the latitude and one with the longitude. In each of these there are thousands of entries. My idea was to map all this variables in a map (lol) where a dot of a color (depending on hr) was placed in the position specified by the latitude and logitude. This is how I am currently doing it. I have a standard activity with google maps. At the end of the onCreate I call:

paint()

What this function does:

/*Paint the dots of locations*/ 
private void paint (){
    //Paint the city with the blood of my enemies
    ArrayList<ArrayList<String>> coordinates = new ArrayList<ArrayList<String>>();
    ArrayList<String> lat = new ArrayList<String>();
    ArrayList<String> lon = new ArrayList<String>();
    ArrayList<String> hr = new ArrayList<String>();
    coordinates = readfile(); #Import file from downloads and process it, takes 0.5sec for over 6000 entries.
    /*Here and down takes 1 minute for the same number of entries*/
    lat = coordinates.get(0);
    lon = coordinates.get(1);
    hr = coordinates.get(2);

    for (int i = 0; i < lat.size(); i++) {
        //paint
        // Add a circle for high heart rate
        if(Integer.parseInt(hr.get(i))>100){
            Circle circle = mMap.addCircle(new CircleOptions()
                    .center(new LatLng(Double.parseDouble(lat.get(i)), Double.parseDouble(lon.get(i))))
                    .radius(10) //size of circle
                    .strokeColor(Color.RED)
                    .fillColor(Color.RED));
        }
        else{
            Circle circle = mMap.addCircle(new CircleOptions()
                    .center(new LatLng(Double.parseDouble(lat.get(i)), Double.parseDouble(lon.get(i))))
                    .radius(10) //size of circle
                    .strokeColor(Color.GREEN)
                    .fillColor(Color.GREEN));
        }

    }
}

I added some logs to check the times, and the importing and processing of the file takes 0.5 seconds. The rest takes 1 minute.

What would be a way of optimizing this? The idea I had was if it was possible to take all the spots that are repeated (same latitude and longitude) and use either the most common hr value or the average(?). I don't know how much this would help though if the user is on the move.

Any suggestions?

Upvotes: 0

Views: 68

Answers (2)

user2413972
user2413972

Reputation: 1355

Test data:

1:1, 1:2, 3:4, 2:3, 5:5

Not very clear what to do without your domain. The standard solution to this situation is the omnibus multiple markers in a large one. Etc =>

1:1.5, 2.5:3.5, 5:5

Also, I do not see you limit the visibility zone. Do I have to show you everything? If you see only 0:0 to 2:2, you need to visible only:

1:1, 1:2

Upvotes: 1

Rey Libutan
Rey Libutan

Reputation: 5314

These simple things come to mind.

  1. Initialize your ArrayLists with initial capacity to reduce its resize (this is somewhat a heavy task) by doing something like below. I don't know the code for readFile() so do that yourself.

    ArrayList<String> lat = new ArrayList<String>(6000);

  2. Do not put lat.size() in the for condition.

    for (int i = 0; i < lat.size(); i++) {

  3. Why maintain 3 List? I don't know the specific requirements but if my assumption is correct, you could do something like ArrayList<MyCustomObjectWhichHoldsTheThreeValuesInOneClass>

Upvotes: 3

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